1. Description of the Related Art
The present invention relates to a routing route control system and a routing route controlling method capable of performing the route switching at the time of route trouble and under predetermined decision conditions, by combining the routing protocol with SNMP (Simple Network Management Protocol) and ICMP (Internet Control Message Protocol) as the network management protocol in the route control in the IP (Internet Protocol) network.
2. Description of the Related Art
The route change of the IP network in the prior art is controlled by the routing protocol. In the control executed by the routing protocol, the route can be switched at the time of route trouble by exchanging the information between the routers, nevertheless the route change cannot be performed under particular conditions.
Also, in Patent Application Publication (KOKAI) Hei 10-23060, there is disclosed the network system that can be restored in a short time at the time of trouble by switching the function from the master router to the back-up router when the trouble occurs in the particular router.
FIG. 12 shows the network system set forth in Patent Application Publication (KOKAI) Hei 10-23060. A plurality of terminal devices 49-1 to 49-N are connected via a LAN 55 and also connected the terminal devices 53-1 to 53-M via the master router 41, the back-up router 42, the WAN 54, the master router 50, the back-up router 52, and the LAN 56. When the trouble occurs in the master router 41, the trouble informing portion 43 informs the back-up router 42 of occurring of the trouble, and loads the trouble occurring information into the trouble information table 45 and also copies contents in the routing table 44 into the routing table 47 in the back-up router 42 via the input/output device 48 and the external input/output processing portion 46. Thus, when the information are transmitted to the master router 41, the back-up router 42 can function in place of the master router 41, whereby the restoration and the route switching can be controlled in a short time at the time of trouble in the master router.
In order to switch the route at the time of route trouble, the particular back-up router having the route switching function is needed in the network system in the prior art, and thus the system for satisfying such need must be constructed. Also, there is the problem that the route cannot be switched under the particular conditions other than the trouble.